Stator vane assembly for a turbomachine

Abstract

A stator vane assembly for a gas turbine engine (10) compressor (16) comprises a plurality of circumferentially arranged stator vanes (44A) and a plurality of circumferentially arranged load bearing struts (46). The leading edges (45,47) of the stator vanes (44A) and the struts (46) are arranged in a common plane. The leading edges (45,47) of the stator vanes (44A) and the struts (46) have substantially the same profile. The spacing (B) between adjacent struts (44A) in any group is the same. The spacing (C) between the suction surface (50) of one of the struts (46A) of the adjacent pair of struts (46) and an adjacent stator vane (44A) is less than the spacing (B) between adjacent stator vanes (44A) and the spacing (D) between the pressure surface (52) of the other of the struts (46B) of the adjacent pair of struts (46) and an adjacent stator vane (44A) is greater than the spacing (B) between adjacent stator vanes (44A) to equalise aerodynamic loading of the stator vanes (44A) and to reduce the aerodynamic losses of the struts (46).

We claim: 
     
       1. A stator vane assembly for a turbomachine comprising a plurality of circumferentially arranged stator vanes and a plurality of circumferentially arranged load bearing struts, each stator vane having a leading edge, a trailing edge and a chord length, each strut having a leading edge, a trailing edge, a pressure surface, a suction surface and a chord length, the chord length of the struts being greater than the chord length of the stator vanes,   the stator vanes being arranged in groups between adjacent pairs of struts, each group of stator vanes comprising a plurality of stator vanes, the circumferential spacing between adjacent stator vanes in a group being substantially the same,   the circumferential spacing between adjacent struts being substantially the same,   the circumferential spacing between the suction surface of one of the struts of an adjacent pair of struts and an adjacent stator vane being less than the circumferential spacing between adjacent stator vanes in the group and the circumferential spacing between the pressure surface of the other of the struts of the adjacent pair of struts and an adjacent stator vane being greater than the circumferential spacing between adjacent stator vanes in the group to equalise aerodynamic loading of the stator vanes and to reduce the aerodynamic losses of the struts.   
     
     
       2. A stator vane assembly as claimed in claim 1 wherein the leading edges of the stator vanes and the leading edge of the struts are arranged substantially in a common plane. 
     
     
       3. A stator vane assembly as claimed in claim 1 or claim 2 wherein each strut comprising an upstream portion and a downstream portion, the stator vanes and the upstream portions of the struts have substantially the same profile. 
     
     
       4. A stator vane assembly as claimed in claim 1 wherein the circumferential spacing between the suction surface of one of the struts of the adjacent pair of struts and an adjacent stator vane being approximately 60% of the circumferential spacing between adjacent stator vanes and the circumferential spacing between the pressure surface of the other of the struts of the adjacent pair of struts and an adjacent stator vane being approximately 140% of the circumferential spacing between adjacent stator vanes. 
     
     
       5. A stator vane assembly as claimed in claim 1 wherein the turbomachine is a gas turbine engine, the gas turbine engine comprising a compressor, a combustion chamber assembly and a turbine. 
     
     
       6. A stator vane assembly as claimed in claim 5 wherein the stator vanes are compressor stator vanes of the gas turbine engine. 
     
     
       7. A stator vane assembly as claimed in claim 6 wherein the stator vanes are compressor outlet guides vanes arranged to supply air to the combustion chamber assembly of the gas turbine engine. 
     
     
       8. A stator vane assembly as claimed in claim 5 wherein the gas turbine engine comprises a fan arranged within a fan duct defined at least in part by a fan casing, the fan casing being supported by fan outlet guide vanes, the stator vanes are fan outlet guide vanes arranged to supply air to a fan duct nozzle. 
     
     
       9. A stator vane assembly as claimed in claim 2 wherein the downstream portions of the struts are wedge shaped in cross-section. 
     
     
       10. A stator vane assembly as claimed in claim 1 wherein the leading edges of the stator vanes are arranged downstream of a plane joining the leading edges of the struts. 
     
     
       11. A stator vane assembly as claimed in claim 1 wherein the trailing edges of the stator vanes are arranged upstream of a plane joining the trailing edges of the struts. 
     
     
       12. A stator vane assembly for a turbomachine comprising a plurality of circumferentially arranged stator vanes and a plurality of circumferentially arranged load bearing struts, each stator vane comprising a leading edge, a trailing edge and a chord length, each strut having a leading edge, a trailing edge, a pressure surface, a suction surface and a chord length, the chord length of the struts being greater than the chord lengths of the stator vanes,   each strut comprises an upstream portion and a downstream portion, the stator vanes and the upstream portions of the struts having substantially the same profile, the downstream portions of the struts are wedge shaped in cross-section,   the stator vanes being arranged in groups between adjacent pairs of struts, each group of stator vanes comprising a plurality of stator vanes, the circumferential spacing between adjacent stator vanes in a group being substantially the same, the circumferential spacing between adjacent struts being substantially the same,   the circumferential spacing between the suction surface of one of the struts of an adjacent pair of struts and an adjacent stator vane being less than the circumferential spacing between adjacent stator vanes in the group and the circumferential spacing between the pressure surface of the other of the struts of the adjacent pair of struts and an adjacent stator vane being greater than the circumferential spacing between adjacent stator vanes in the group to equalise aerodynamic loading of the stator vanes and to reduce the aerodynamic losses of the struts.